Film developing process

ABSTRACT

THE QUALITY OF SILVER HALIDE IMAGES IS ENHANCED AND/OR FILM DEVELOPING TIME REDUCED BY THE RELATIVE DISPLACEMENT OF DEVELOPER TO FILM IN THE PRESENCE OF A MAGNETIC FIELD. A FEATURE OF THE INVENTION IS ALSO DISCLOSED IN WHICH DURING   THE DEVELOPMENT PROCESS ENZYMER ARE ADDED, THEREBY ENHANCING STILL FURTHER THE IMAGES AND/OR FILM DEVELOPING SPEED.

Aug. 27, 1974 FILM DEVELOPING PROCESS Filed May 15. 1975 Lam/711:1 :1 mnanl n I N /6 u Jnnauscmarj S Z2 Z4 3 Sheets-Sheet 1 M. JACOBSON 3,882,178

Aug. 27, 1914 M. JACOBSON 3,832,178

FILM DEVELOPING PRocEss Filed May 3. 1975 3 Sheets-Sheet 9 UMQE WWWQQNR N W QNQQEEM TI 1% Q (law/ m) vymad 9/v/A 70552 M. JACOBSON FILM mavmorme PROCESS Aug. 27, 1914 3,882,178

Filed May 5, 1973 3 Sheets-Sheet 374N014 RD E- 4 PROCE 5 5 171/ Vf/V TI (/5 P206555 R ELAT/VE L06 EXPOSURE FlG.3b

United States Patent 3,832,178 FILM DEVELOPING PROCESS Max Jacobson, 56 E. 87th St., New York, N.Y. 10028 Continuation-impart of applications Ser. No. 142,396 and 142,413, both dated May 11, 1971, both now abandoned. This application May 3, 1973, Ser. No.

Int. Cl. G03c 5/24, 5/26 US. Cl. 96-50 R 7 Claims ABSTRACT OF THE DISCLOSURE The quality of silver halide images is enhanced and/ or film developing time reduced by the relative displacement of developer to film in the presence of a magnetic field. A feature of the invention is also disclosed in which during the development process enzymes are added, thereby enhacing still further the images and/or film developing speed.

BACKGROUND OF INVENTION This application is a continuation-in-part of my co pending applications Ser. Nos. 142,413 and 142,396, entitled Film Developing Process, filed May 11, 1971, and Improved Film Processing Method Employing an Enzyme Catalyst, filed May 11, 1971, respectively, now abandoned.

The process to be described herein has broad applications to all film transparencies of the silver halide type, including as diverse transparencies as X-ray negatives and commercial color slides.

In the development of photographic images, the attained detail or the color contrast from a given exposure is determined by the number of exposed halide grains which have been reduced to metallic silver. In the case of color, the metallic silver has associated dyes; however, the premise remains the same. Too energetic a reducing agent in the chemical developer causes an overabundance of exposed silver halide grains to be converted into silver, thereby obscuring the image due to a rise in the general fog level in the film.

On the other hand, too weak a chemical reducing agent reduces an insufiicient number of the exposed halide grains and loses contrast and detail. It is normal practice in the developing art to err on the latter side, so that even the most active of the conventional developers causes only a portion of the exposed silver halides to be reduced. Image optimization in terms of definition, contrast, color balance, brilliance and saturation is seldom, if ever, achieved.

SUMMARY OF THE INVENTION Briefly, the invention is predicated upon the concept of impinging a magnetic field upon a negative being developed while the developer and film are being translated relative one another.

DESCRIPTION OF THE DRAWING To the accomplishment of the above and to such further objects as may hereinafter appear, the present invention relates to an improved film developing process, substantially as described in the following specification taken together with the accompanying drawings wherein:

FIG. 1 discloses an arrangement for moving the developer relative to the film in the presence of a magnetic field;

FIG. 2 illustrates an alternative arrangement for moving the film relative to the developer in the presence of a magnetic field; and

FIGS. 3a and 3]; illustrate a comparison of E4 Ektal chrome processing and the inventive processing for high speed Ektachrome film.

Patented Aug. 27, 1974 ice It is obviously commercially desirable to provide a procedure for developing film more rapidly. This makes the image more quickly available for inspection and use and increases the film throughput rate of batch processing.

It is known that various materials when added to the developer solution speed the operation. However, such additives have uniformly operated on the film halide, thereby decreasing the contrast and color definition in the formed image.

In accordance with the principles of the present invention, I have invented a procedure wherein either development time may be reduced, or, alternatively, conventional development time employed leading to image enhancement, both in contrast and definition. Thus, for example, it has been found that the conventional development time of seven minutes realizes an improvement of 1 /2 F stops when using the inventive process. Increasing the development time two minutes results in 2 F stop improvement when the process is employed, and a development time of 11 minutes results in a 3 to 4 F stop improvement without significant color shift. All of the foregoing was obtained using commercially available Ektachrome film. Alternatively, results fully equivalent to seven minute commercial development may be shortened to three minutes using the inventive process.

For purposes of illustration, an example shall be explained in which commercial Ektachrome film is subjected to the process. It will be appreciated, however, that the description applies as well to any silver halide film.

Development of typical Ektachrome film is a multistep process including: a pre-hardener stage to permit development at elevated temperatures; a neutralizer stage which neutralizes the hardener; a first developer stage in which the image is developed; a first stop stage which is an acetic acid wash; a wash stage (with water); a color developer stage; a second stop stage; a second wash stage; a bleach stage, which bleaches out certain amounts of the silver; a fixer stage for bringing out color; a wash stage; and finally a stabilizer stage for permanency.

The process to be described will be introduced in the first developer stage. It is to be appreciated, however, that it may be used as well in the color developer stage.

Turning now to FIG. 1, the film 16 to be developed may be seen mounted upon a reel 14 which is axially affixed by means of a depending arm 10 to cover 18 in order to stabilize the reel in space. In the example, just sulficient frames are located in the reel to make one full revolution, although it will be appreciated by those skilled in the art that the film may be spaced spiral wound on the reel and the reel disposed in attitude to permit the desired developer flow. The combination just recited is enclosed within a commercial mixer, comprising an envelope 12 and a base 20 housing a motor (not shown) driving a blade set 21. Permanent magnets 22 and 24 of the conventional (or horseshoe) type are juxtaposed outside the envelope 12 to cause the magnetic field to pass through the film being developed.

I have found the following parameters to yield the best results: The motor speed is controlled so as to result in a developer movement in the envelope 12 which produces from S0 to 500 inches per second of developing liquid past the film. Measurement was obtained by stroboscopically analyzing the current in cycles per second at film location and thereby determining the transport speed of liquid relative film.

The imposed magnetic field, measured by a gaussmeter probe located within the solution, provides good results in the range of 100 to 900 gauss. The developer temperature is preferably F. Surprisingly, it has been found that the use of a magnetic field results in a temperature drop within this solution of between 2 to 5, requiring the solution to be heated to maintain its temperature stability. This may be easily accomplished by any conventional method. It may also be accomplished by preheating to 87 F. and permitting the solution to attain an 85 F. steady state.

While the foregoing describes the general parameters for transporting the liquid relative the film and the magnetic field strength, I have found that the best results obtain when transport of liquid relative film is in the area of between 100 and 300 inches per second and the magnetic field is between 200 and 400 gauss.

It will be appreciated that too slow a transport of liquid relative the film creates no discernible difference from conventional techniques, while too fast a transport oxidizes the solution.

While in the foregoing we have shown an example in which the transportation is of liquid relative film, it will be appreciated by those skilled in the art that similar results may be obtained by transporting the film relative to the liquid, so long as the relative speed of transport, one to the other, remains within the defined parameters. Further, the same efiect has been determined to exist in the presence of an alternating magnetic field.

FIG. 2 illustrates an embodiment in which the film 30 is transported through a pair of rollers 32 and 34, mounted in a vessel 40. Rollers 32 and 34 are preferably compressively acting upon film 30 to enable handle 42 to move the film through the rollers. The rollers 32 and 34 comprise plastic encapsulated magnets, poled to attract and journalled in the walls of vessel 40 to permit their rotation. Because high speed transport of this nature is difficult in the order of magnitude desired, it has been found that slower speeds may be augmented by including a commercially available ultrasonic vibrator 50 beneath the vessel, thereby creating developer vis-a-vis film motion, as desired. Again, the suggested field strength is between 150 and 300 gauss. Too strong a magnetic field blocks development; too weak a field creates no difference from conventionally available processes.

I have also found that the addition of a biological enzyme to standard developer solution in minute quantities further enhances the resultant image. In particular, I have found that enzymes added to the developer, ranging in quantities from 1 part in 10,000 by volume to 1 part in 1,000,000 by volume, is surprisingly effective. The biological additions may comprise, for example, and without limitation, Aspergillus, placenta, a mixture including vitamins AB C and E, sorbitol, testosterone, estrogen substances, celestrones and homoganate derivatives.

With the foregoing process, the quality of negative images, in particular the definition, background and detail, not theretofore apparent, will manifestly enhance. With X-ray negatives, for example, after using the process, it was possible to observe soft tissues, such as lymph glands, which were not previously observable. Additionally, greater depth perception is achieved because of the visual clues provided by the improved shadow detail.

With color images vast differences between the color contrast and color brilliance are observable with the naked eye when the process according to the invention is compared with the conventional process.

A 35 mm. camera, equipped with a specially selected lens of very high image quality, was mounted on an optical bench. At the other end of the bench, a low contrast MIL- resolving power target was mounted, together with several color patches. Uniform tungsten lighting was established. A through-focus run was first made to establish best focus setting, and best exposure. Several rolls of High Speed Ektachrome (Type B) film were exposed, over an eight-stop exposure range from 4 stops to +3 stops in one-stop increments. On all rolls, a standard 21 step sensitometric exposure was made, using the 1B sensitometer.

Several of these rolls were processed according to the invention and one roll was processed in the standard Kodak E-4 chemistry.

When the test films were returned, each frame was mounted individually in a 2 by 2 slide mount, and coded, including the control set of images. The images consisted of 37 frames, including the standard Ektachrome E-4 process and the inventive process (at 200 inches/second and 300, gauss) were then shuffled in a totally random order, and each resolving power target image was read under a microscope. A range of magnification was available aud the sub-stage illumination was controllable in order to establish optimum viewing conditions for overexposed, underexposed, and normal images. The readings were converted into cycle-per-millimeter values, the read- 'ings for each frame were averaged, and the averages plotted as a function of exposure, as shown in FIG. 3a.

The step tablets were also read on a MacBeth densitometer, using Status A filters (for reversal films), and the curves plotted as show in FIG. 3b.

The standard process produced a peak low contrast (2:1) resolution of 46 cycles per millimeter, at an exposure of two stops above what was considered normal, based on overall examination of the transparency. For normal exposure, the resolving power was about 41 cycles per millimeter, or 11% lower. For exposures less than normal, the inventive process showed about the same results. The slight difference in curve shape is well within the experimental variance for this type of test.

P or exposures greater than normal, the inventive process showed a rapid and greater percentage loss than the E-4 process. For example, at +3 stops, the E-4 value is 43 cycles per millimeter, compared with 27 cycles per millimeter for the inventive sample. This i attributed to a greater loss in image contrast with the inventive process at the over-exposure end, since the process does produce an effective increase in speed. The resolving power for the inventive process at +1 stop is almost identical with that for the E-4 process at +3 stops (41 versus 43 cycles per millimeter).

To examine image structure in terms of visual appearance, images representing the best compromise between maximum resolving power and overall exposure for the 134 control process and the inventive process were selected. Photomicrographs (about 30X) were made of the central areas on Polaroid Polacolor film.

Although there is little difference in resolving power, these photomicr-ographs showed a marked difference in granularity. The inventive image structure is smoother, so much so that the slides were re-examined to be sure the photornicrograph was properly focused (defocusing would make grain structure appear less prominent). The examination confirmed that in all slides processed in accordance with the invention there is a reduction of granularity, or dye clumping (there is no silver remaining in the reversal image).

In FIG. 3b, three High-Speed Ektachrome sensitometry strips, processed in accordance with the invention, were compared to a control strip (E 4). Speed increases of up to 4.7 times were achieved with the inventive process. The inventive strips showed some modeling, and a slight green tint which could be corrected with filtration.

It is postulated from the resultant efiect that the process frees additional silver halide grains, which were only partially developed by conventional photographic development processes, and does so most in middle density areas. In the middle density areas where some silver halide grains have been freed and others have not, the treatment described develops additional grains bringing about increased shadow detail. In color film, of course, the halides are coupled with dyes and results in more intense colors. No specific physical mechanism for the above functioning can be definitively stated.

1While the principles of the invention have been described in connection with specific apparatus and steps,

it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention as set forth in the objects and in the accompanying claims. Thus, for example, whereas, with respect to the first figure a methodology is shown which moves the development solution past the film, similar results would obtain if the film were linearly transported in a canal through a development solution at the speed suggested with a magnetic field toroidally induced.

What is claimed is:

1. In a development process for developing silver halide type negative films, the improvement in the development stage of said process comprising the steps of simultaneously transporting the film relative the developer between 50 to 500 inches per second, and imposing on said film a magnetic field of the order of 100 to 900 gauss.

2. The method claimed in claim 1, further comprising the steps of maintaining developer temperature at approximately 85 F.

3. The method claimed in claim 1, wherein the relative speed of developer and film is from 100 to 300 inches per second, and the imposed magnetic field is of the order of 100 to 300 gauss.

4. The method claimed in claim 1, in which said film is color film and in which said process is applied at the first development stage.

5. The method according to claim 1, further comprising the addition of enzyme to the developer solution.

6. The method according to claim 5, wherein said enzyme is added to the developer in the proportion of between 1 to 10,000 parts to 1 to 1,000,000 parts by volume.

7. The method according to claim 6, wherein the enzyme is selected from the group consisting of aspergillus, placenta, a mixture including vitamins AB C and E, sorbitol, testosterone, estrogen substances, celestrones and homoganate derivatives.

References Cited UNITED STATES PATENTS 3,157,500 11/1964 Abbott et a1. 9648 3,567,930 3/1971 Jacobson 9648 MARY F. KELLEY, Primary Examiner US. Cl. X.R. 

